Abstract 1. Important scientific accomplishments supported by R37HL068546. Since submission of this proposal in the fall of 2008, the Pl and his laboratory have published a total of 51 manuscripts, of which 33 were supported by this proposal. Our productivity has been excellent recently; just in the first four and one half months of 2013, we have published eleven papers, of which seven appeared in the Journal of Allergy and Clinical Immunology, the leading Allergy-Immunology journal (impact factor approximately 11) and 7 were supported by this grant. This report is divided into sections that are oriented toward selected relevant ongoing projects. Many of the in vivo studies described in this report utilized patients with active chronic rhinosinusitis (CRS) and controls having surgery for non-inflammatory conditions. The Northwestern University (NU) group obtains and analyzes tissue samples, lavage and epithelial scrapings from over 250 tertiary care patients per year, enabling the translational work described in this proposal. One of the important studies in the proposal is to perform a clinical trial testing the impact of prednisone treatment on innate immunity, barrier, adaptive immunity and inflammatory responses in CRS. As described in this report, we are near completion of sample collection and we will very soon have a rich collection of important human samples from patients treated with prednisone, or not treated, with which to test some of the hypotheses described in the original proposal.